SAP's move is seen as a direct attack on Oracle's cloud-based tools for human resources management. So the Californian empire strikes back. Taleo tucks right into Oracle's recently closed $1.5 billion acquisition of customer management expert RightNow Technologies. The rivalry between SAP and Oracle has made buyout bait out of pretty much any cloud-based business management expert you'd care to name.

Oracle is sticking with relatively cheap targets. RightNow went for 5.5 times forward sales, SuccessFactors is selling for eight times forward revenue, and Taleo's price tag amounts to roughly five times estimated 2012 sales.

With sales multiple standards like that, perhaps the buyout binge in cloud-computing enterprise software is coming to an end. The only obvious target left on the shooting range is LivePerson (NAS: LPSN) , which would cost about $1 billion at these multiples. Bigger potential targets would put serious strain on even Oracle's bulging coffers.

There's no question that cloud-computing business tools are the way forward. Workers are getting mobile, and it's just not practical to install business tools on myriad laptops and smartphones when you can just make the same functionality easily available in a centralized model. That's why Oracle and SAP are investing billions in this space, and why the cloud model is making traditional software powers very nervous.